1. Field of the Invention
This invention relates to an improvement in a vehicle hood apparatus having an actuator for lifting a vehicle hood to an appropriate extent upon collision of an object with the vehicle.
2. Description of the Related Art
An object colliding with the front part of a running vehicle is often likely to jump up and fall on its hood. It is often necessary to protect such an object from any impact produced by such a collision. Therefore, there are known vehicle hood apparatuses for lifting the hood of a vehicle to some extent upon collision of an object with the vehicle and thereby reducing any impact acting upon the object, as disclosed in, for example, Japanese Patent Laid-Open Publication No. HEI-9-315266.
The apparatus disclosed therein includes a control system which is informed of the collision of an object as detected by a pedestrian collision sensor attached to a front bumper, and a hood lifting and holding mechanism which lifts the hood and holds it in its lifted position in accordance with information from the control system. The hood lifting and holding mechanism (hereinafter called the actuator) has on its rod a hook which is fastened to the vehicle body for holding the hood. The hook is fastened to the rod rotatably by a supporting pin and urged by a compression spring.
The hook is, however, not always equal in its locked position, but its locking is low in reliability, as it is locked too tightly in some cases, while too lightly in other cases, depending on the quality of the work done for attaching the actuator to the vehicle body, since the actuator is formed with the hook provided on the rod so that the hood is heed by locking the hook to side of car body.
The actuator is not easy to assemble, as it is a difficult job to assemble its small parts, such as hook, supporting pin and compression spring, with the rod.
Moreover, the hood lifted by the actuator is likely to obstruct the sight of the vehicle""s driver since the conventional vehicle hood is to be lifted by on actuator and held in the lifting position, and in any such event, it is desirable that the sight of the driver be recovered quickly.
It is, therefore, an object of this invention to provide a vehicle hood apparatus having an actuator which is easier to assemble, while it is mounted in its properly locked position.
It is another object of this invention to provide a vehicle hood apparatus which ensures the quick recovery of the sight of the vehicle""s driver from its obstruction by the hood lifted upon collision of any body with the vehicle.
According to a first aspect of this invention, there is provided a vehicle hood apparatus having an actuator for lifting a vehicle hood to an appropriate extent upon collision of an object with the vehicle, the actuator comprising an actuator block, a cylinder defined by the block, a piston pin extending into the cylinder through one end thereof, a gas generator situated at the other end of the cylinder for raising the piston pin rapidly, a piston retainer situated at one end of the cylinder for retaining the raised piston pin in the cylinder, a locking member capable of projecting into the cylinder for locking the piston pin held in its raised position by the locking member, and an elastic member associated with the locking member for urging it resiliently to project into the cylinder, so that the hood may be lifted by the raised piston pin and held in its lifted position by the locking member.
The locking member is capable of projecting into the cylinder. Upon collision of an object with the vehicle, the gas generator is actuated to raise the piston pin rapidly, and the vehicle hood is lifted by the actuator to a certain extent. The locking member immediately projects into the cylinder to lock the piston pin in its raised position and thereby hold the hood in its lifted position.
As the actuator includes the locking member which is capable of projecting into the cylinder for locking the piston pin in its raised position, the locked position of the piston pin does not depend on the quality of the work done for attaching the actuator to the vehicle body, as opposed to, say, the case where the piston pin has to be locked to the vehicle body. As the locking and elastic members are held in the actuator block, the actuator is easier to assemble than, say, when they have to be held on the piston pin.
According to a second aspect of this invention, there is provided a vehicle hood apparatus having an actuator for lifting a vehicle hood to an appropriate extent upon collision of an object with the vehicle, the actuator comprising an actuator block, a cylinder defined by the block, a piston pin extending into the cylinder through one end thereof, a gas generator situated at the other end of the cylinder for raising the piston pin rapidly, a piston retainer situated at one end of the cylinder for retaining the raised piston pin in the cylinder, a locking member capable of projecting into the cylinder for locking the piston pin held by the locking member in its raised position, the locking member having a hole extending between its front and back sides to maintain an equal gas pressure therebetween, and an elastic member associated with the locking member for urging it resiliently to project into the cylinder, so that the hood may be lifted by the raised piston pin and held in its lifted position by the locking member.
The locking member is capable of projecting into the cylinder. Upon collision of an object with the vehicle, the gas generator is actuated to raise the piston pin rapidly, and the vehicle hood is lifted by the actuator to a certain extent. The locking member immediately projects into the cylinder to lock the piston pin in its raised position and thereby hold the hood in its lifted position.
As the actuator includes the locking member which is capable of projecting into the cylinder for locking the piston pin in its raised position, the locked position of the piston pin does not depend on the quality of the work done for attaching the actuator to the vehicle body. As the locking and elastic members are held in the actuator block, the actuator is easier to assemble.
The locking member has a hole which enables an equal gas pressure to be maintained between its front and back ends, so that it may act rapidly without being affected by the pressure of gas generated by the gas generator.
According to a third aspect of this invention, there is provided a vehicle hood apparatus having an actuator for lifting a vehicle hood to an appropriate extent upon collision of an object with the vehicle, the actuator comprising an actuator block, a cylinder defined by the block, a piston pin extending into the cylinder through one end thereof, a gas generator situated at the other end of the cylinder for raising the piston pin rapidly, a piston retainer situated at one end of the cylinder for retaining the raised piston pin in the cylinder, a locking member capable of projecting into the cylinder for locking the piston pin held by the locking member in its raised position, an elastic member associated with the locking member for urging it resiliently to project into the cylinder, an unlocking device for retracting the locking member to predetermined position to release it from its locking action and a control device for actuating the unlocking device in an approriately timed relation to the locking member, so that the hood may be lifted by the raised piston pin and held in its lifted position by the locking member, while after a certain period of time, the locking member is released from its locking action to allow the hood to be lowered.
The apparatus includes an unlocking device for retracting the locking member to predetermined position to release it from its locking action and a control device for actuating the unlocking device in an approriately timed relation to the locking member. Upon collision of an object with the vehicle, the gas generator is actuated to raise the piston pin rapidly, and the vehicle hood is lifted to a certain extent by the actuator. The locking member immediately projects into the cylinder to lock the piston pin in its raised position and thereby hold the hood in its lifted position. After a certain period of time, the unlocking device is actuated in response to information from the control device to release the locking member to allow the hood to be lowered.
The unlocking device ensures that the hood be lowered so as not to obstruct the sight of the driver if it is no longer necessary to hold the hood by operating the actuator in its lifted position as required for, say, protecting any structure within the hood from any impact caused by an object hitting the hood and deforming it.